Oh, sorry, I forgot to tell you that therapy doesn't work if it only happens once. It isn't a magic, one-time cure from the future.

If you seriously think that killing the girl-- which NONE of us have ANY authority to do-- would have prevented that, then you're a complete idiot. Her Warden should be devising a better plan for her care than "lock her up when she misbehaves, and send her to a therapist once." And we should be doing more than REACTING to everything they do.